| Brown millet is the whole grain of millet after removing the husk,which is mainly composed of cortex,embryo and endosperm.It is in line with the definition of whole grain,and can also be divided into two product methods: entire grain grinding method and millet bran re-adding method.The brown millet is rich in various vitamins,minerals and other nutrients,but its application in food is limited due to its rancidity and poor sensory quality.To solve these problems,from the perspective of stablizing brown millet,the infiuence on the nutritional characteristics and the application of steamed bread were explored.Firstly,on the basis of different production methods of whole brown millet,the optimal stabilization methods of brown millet and millet bran were studied respectively.Brown millet and millet bran was treated by dry heat,moist heat and extrusion method,which regarded the peroxidase residual energy combined,oryzanol content,phytic acid content and storage period of fatty acid value as the main index.The results showed that the best stabilization methods for brown millet and millet bran were extrusion methods.When the treatment conditions of brown millet was moisture content of 24% and extrusion temperature of 110°C,the treatment conditions of millet bran was moisture content of 24%,extrusion temperature of 120°C,the residual peroxidase activity of each was the lowest,that were respectively 4.81% and 4.73%Secondly,the application of whole brown millet in steamed bread was studied,and the influence of fermentation methods on the quality of brown millet steamed bread were also investigated.The results showed that the best product method of whole brown millet was the re-adding method,and its optimum addition amount in the steamed bread was 20%.On this basis,by comparing the quality of whole brown millet steamed bread made by rapid method(RM),sponge dough method(SDM)and sourdough-retarded sponge dough method(SRSDM),it was found that the hardness of steamed bread fermented by SRSDM was the smallest and the specific volume was the largest,which could reach 3.10±0.01 mL/g.There was no significant difference between the specific volume of steamed bread fermented by RM and SDM,but the structure of steamed bread made by SDM was obviously more uniform and delicate than that by RM.By comparing the SEM images of the proofed dough prepared by the three kinds of fermentation methods,it could be seen that the pores of the dough by SRSDM were uniform,large and full,the pores of the dough by SDM were slightly uniform and elongated,and the structure of the dough by RM was the worst.The sensory scores of all steamed bread prepared by three fermentation methods were higher than 80.0,and the sensory score of steamed bread made by SRSDM(88.0)was the highest.To sum up,the quality of steamed bread prepared by SRSDM was the best.Finally,the effect of whole brown millet flour on the nutritional quality of steamed bread was studied.The results showed that the carotenoid content,total phenol content,DPPH clearance rate,and dietary fiber content of the brown millet steamed bread by SRSDM were higher than that by RM and SDM,while the trend of dietary fiber content is opposite.It indicated that the nutrients of the steamed bread could be effectively improved,and the content of anti-nutritional factors could be reduced by SRSDM.The content of carotenoid,antioxidant in stabilized brown millet steamed bread was lower than that of unstabilized brown millet steamed bread.Compared with unstabilized brown millet steamed bread,the dietary fiber content of stabilized brown millet steamed bread made by SRSDM decreased by 19.0%,and the dietary fiber content increased by 11.2%,but the contents of both were higher than those of the control steamed bread.It showed that the stabilization treatment increased the dietary fiber content in the brown millet steamed bread to a certain extent,and in general,the addition of the whole brown millet flour is still beneficial to increase the nutrient content of the steamed bread. |
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